1. Field of the Invention
The present invention relates to a guard device for needles used in medical practice and, more particularly, to visually confirmable positionally lockable guard devices for single and double ended needles.
2. Description of the Prior Art
A needle shield which must be removed anteriorly from a needle hub before a syringe can be used for a medical procedure is well known. Remounting such a shield requires a user to insert the point of the needle into the open end of the shield and draw the shield posteriorly over the needle until it encloses the needle. Such a removable needle shield contains several limitations, including: (1) after a liquid medicament has been drawn up in a syringe, medical personnel may occasionally delay the administration of the medicament, which delay requires retrieval and replacement of the needle shield to prevent contamination of the sterile needle and creates extra steps for busy medical personnel; (2) medical personnel often remove this needle shield by holding the needle shield between their teeth or lips. This practice has been associated with accidental self-puncture in the face or other body parts; (3) in order to recover a used needle with a previously removed needle shield, it is necessary to replace the needle shield back over the pointed end of the used needle, which replacement increases the risk to medical personnel of accidentally puncturing themselves with the pointed end of the used needle; and, (4) if the needle has been accidentally bent during a medical procedure or if the needle shield is replaced over the needle at an incorrect angle, the needle point may inadvertently pierce the side of the needle shield and puncture the fingers or hand.
In order to avoid problems attendant needle shields which must be remounted posteriorly from a location anterior of the needle point, various devices have been developed. Several of these devices include shields translatable posteriorly upon the barrel of a hypodermic syringe to expose the needle. To re-enclose the needle within the shield, anterior translation of the shield is effected. Unless the shield is locked at its anterior end of travel, inadvertent uncovering of the needle may occur. This results in a potential for exposure to needle stick or contact with body fluids upon the needle. If a lock is used it must not be unlockable during normal handling of a discarded syringe and an indication of the locked state should be visually apparent without having to test the positional security of the shield. Furthermore, such indication should be evident in an unambiguous manner under low light conditions.